Is this a traffic revolution? Circular intersections known as roundabouts gaining popularity locally

In right location, they reduce traffic, crashes

CINCINNATI -- Tri-State traffic is going in circles, and it doesn’t appear to be stopping anytime soon.

More than 30 years after Clark Griswold spent an entire day circling London’s famous Lambeth Bridge roundabout in 1985’s “European Vacation” -- “There’s Big Ben, kids! Parliament!” -- Cincinnati-area planners have grown excited about roundabouts.

“We are trying different things, and roundabouts are definitely tools in the toolbox that we think can be a real benefit,” said Ted Hubbard, Hamilton County engineer, who has studied the use of roundabouts across the country to determine their effectiveness in increasing safety without significantly adding to the cost of projects. “It is a tool in the toolbox, but it’s not right for every location.”

Cincinnati and Northern Kentucky, however, have deemed it the right tool for several locations. Roundabout construction is part of the plans for a number of upcoming transportation projects, including:

  • The intersection of Fields Ertel Road and Columbia Road (recognized as Lebanon Road in Hamilton County).
  • The intersection of Plainfield and Sycamore roads.
  • The intersection of Bridgetown Road and Shady Lane.
  • The intersection of Kilby and Simonson roads.
  • Two on KY 9/AA Highway, one at the base of the Veterans Bridge and another at the base of the Taylor Southgate Bridge. 

Long used in Europe and growing more popular in the United States, roundabouts are circular intersections in which traffic flows almost continuously in one direction around a central island and drivers exit at the right of the desired road. The continuous traffic flow allows drivers to avoid waits at stops signs or signals and significantly increases safety, according to federal studies.

Insurance Institute for Highway Safety studies of U.S. intersections that were converted from traffic signals or stop signs to roundabouts have found reductions in injury crashes of 72-80 percent and reductions in all crashes of 35-47 percent. The tight circle of a roundabout and the curvature of the road leading to it force drivers to slow down, making the most severe types of intersection crashes -- right-angle, left-turn and head-on collisions -- unlikely.

Additionally, Hubbard said, roundabouts are more aesthetically pleasing and better for the environment because of reduced emissions and fuel consumption from a reduction in vehicle idling. The reduced speed of vehicles also improves pedestrian safety. Roundabouts are one of nine evidence-based safety countermeasures recommended by the Federal Highway Administration.

The first modern roundabouts in the United States were constructed in Nevada in 1990. According to federal authorities, there are around 5,000 modern roundabouts in use in the United States. Hundreds more are constructed every year. Carmel, Indiana, one of the cities researched by Hubbard, has become internationally known for its roundabout network. Since the late 1990s, Carmel has been replacing signalized intersections with roundabouts. The city will celebrate Nov. 17 the opening of its 100th roundabout, more than any other city in the country.

Costs for constructing a roundabout vs. a traditional intersection are typically comparable, though the total expenditure depends largely on the area and what must be disturbed for the installment to occur. Another positive factor for the roundabouts is the cost savings of not needing traffic signals or the electricity to run them.

The dense traffic, both vehicular and pedestrian, at the Banks development made it an ideal location for a small roundabout, according to Phil Beck, the Banks public partnership project executive. The roundabout, located at the north end of the Suspension Bridge, makes pedestrian crossing easier and improves traffic flow on and off the bridge, he said.

“It works out real nicely in that area, and it keeps vehicle speeds down. It forces you to be alert, and it’s a high pedestrian area -- so not only does it function nicely from a vehicle standpoint, but it inserts a degree of safety,” said Beck. “Most people enjoy or admire it. People accidentally cross the bridge (into Ohio) sometimes and instead of having to take a bunch of one-way streets to find their way back, they can just take the loop-to-loop and be right back on the bridge.”

Though the installation of a roundabout in an area unaccustomed to them may require a learning curve from drivers, the benefits typically far outweigh the drawbacks, Hubbard said. For those areas where they are deemed appropriate for the land use, he listed concern for the vision-impaired as the only disadvantage to roundabouts over traditional intersections.

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